50 for the Future – Green roofs

Our recent publication, 50 for the Future, lists 50 things that we believe should happen in Scotland over the next 50 years to benefit both people and wildlife. In this week's 50 for the Future article, Dusty Gedge, Director of livingroofs.org and the current President of the European Federation of Green Roof and Walls Associations, discusses the possibilities for greening Scotland's rooftops.

Number 25: Make the provision of habitat such as green roofs and walls mandatory in all new buildings and set ambitious targets for retrofitting green roofs to existing buildings in every local authority in Scotland.

Green roofs and walls are taking root in cities across the world. It’s time for Scotland to embrace them and the many benefits they bring.

Of course there is a tradition of turf roofs on crofters’ houses on islands and parts of the mainland, but with a new approach, the creation of useful, nature-rich habitats could be achieved on buildings across the whole country. To achieve this, the Scottish Government and charities such as the Scottish Wildlife Trust should work to ensure there are new mandatory policies for the construction of green roofs on new building stock, and that these are then backed up with specific performance criteria for nature.

Turf and sedum roofs are what most people imagine when they hear the term 'green roof'…

Turf and sedum roofs are what most people imagine when they hear the term 'green roof', and there are indeed a few sedum roofs on commercial buildings in Glasgow, Edinburgh and other cities in Scotland. Whilst these should certainly be celebrated, there is so much more that could be achieved for wildlife at roof level in Scotland. These could be locally specific – why not a machair green roof in the Hebrides or a sand dune roof in Ayr?

Mandatory laws that are in place around the world tend not to be backed up with supplementary guidelines on how to deliver the right type of vegetation for the local fauna. Whilst there is no mandatory policy in the UK, there is now a policy that has an ‘expectation’ in London. This has worked well in the capital since 2008 and is backed up by specific guidelines on how to deliver biodiversity benefits. Unfortunately, neither mandatory policies nor a strong culture around green roofs currently exists in Scotland.

I was recently in Edinburgh where I discussed how a heather moor could be created on a hotel in the Highlands. Merging the buildings into the surrounding landscape would of course lessen the visual impact, but it would also compensate for the loss of habitat. Having done a quick review of the habitats listed in the Scottish Biodiversity Action Plan, it may surprise readers that many of these could be effectively replicated at roof-level.

The easiest is calcareous flower-rich grassland. This is common on roofs in Switzerland, where there is an ecological compensation standard. Acid and montane grasslands, and even dwarf shrub heath could be replicated with good design on rooftops. I have even seen bogs on green roofs, where sundews flourish.

There will be many in the construction industry who will resist such an approach. It is generally in their DNA to seek simple homogenous solutions to the challenges they face, so it is only through new mandatory policy and guidelines that these roof-level habitats in Scotland could be delivered.

Greening the roofs of existing buildings has its challenges but is certainly possible. The first task needs to be to map existing roofs. Following this, roofs should be selected based on their ability to provide the greatest biodiversity and other co-benefits. I have provided some information along these lines to Aberdeenshire Council.

We will also need to create new mechanisms for financing the retrofitting of green roofs such as offsetting where green roofs on new developments may not be possible.

Creating new developments with green roofs and providing a mechanism to deliver on existing building stock will make Scottish cities more resilient. Furthermore, if this is done well and with the right criteria, it will provide new habitat for Scotland’s wildlife, right in the heart of the country’s cities.

Let us know your thoughts by emailing thefuture@scottishwildlifetrust.org.uk or Tweet @ScotWildlife using #50fortheFuture.

Livingroofs.org is currently undertaking a survey on the barriers to green infrastructure uptake in the UK – we would be grateful if you take part.

Dusty Gedge is Director of Livingroofs.org and the current President of the European Federation of Green Roof and Walls Associations. He is also a member of several nature conservation organisations in the UK, including the RSPB and the Kent Wildlife Trust.